Merge 22118a2a97 into 45333e0a31

README.md

@@ -486,8 +486,45 @@ CacheProvider.setCache(new Cache() {
 });
 ```
 
+### Custom Path Functions
 
+If you want to implement you own path functions, create your PathFunction implementation.
+Initializing PathFunctionFactory should only be done when your application is being initialized.
 
+```java
+
+class MyPathFunction implements PathFunction {
+
+	public static final String NAME = "mypathfunc";
+
+	@Override
+	public Object invoke(
+		String currentPath,
+		PathRef parent,
+		Object model,
+		EvaluationContext ctx,
+		List<Parameter> parameters
+	) {
+		// Do something here
+
+		return model;
+	}
+}
+
+// Example application initialization
+class ApplicationBoot {
+	public static void main(String[] args) {
+
+		PathFunctionFactory.add(
+			MyPathFunction.NAME,
+			MyPathFunction.class
+		);
+
+		PathFunctionFactory.init();
+	}
+}
+
+```
 
 
 

json-path/src/main/java/com/jayway/jsonpath/PathFunctionFactory.java

@@ -0,0 +1,80 @@
+package com.jayway.jsonpath;
+
+import com.jayway.jsonpath.internal.function.PathFunction;
+
+import java.util.Collections;
+import java.util.Map;
+
+public class PathFunctionFactory {
+
+	private static boolean initialized = false;
+
+	/**
+	 * by default, we add th common path functions
+	 */
+	private static Map<String, Class> functions = com.jayway.jsonpath.internal.function.PathFunctionFactory.getFunctions();
+
+	/**
+	 * Add a single custom path function
+	 * Should only be done when your application is being initialized
+	 *
+	 * @param name  The name of the function
+	 * @param clazz Class of a function
+	 * @throws InvalidPathException
+	 */
+	public static void add(String name, Class clazz) throws InvalidPathException {
+		assertNotInitialized();
+		if (functions.containsKey(name)) {
+			throw new InvalidPathException("Path function with name: " + name + " already exists");
+		}
+
+		functions.put(name, clazz);
+	}
+
+	/**
+	 * Add a map custom path function
+	 * Should only be done when your application is being initialized
+	 *
+	 * @param functionMap The name of the function as key, Class of a function as Value
+	 * @throws InvalidPathException
+	 */
+	public static void add(Map<String, Class> functionMap) throws InvalidPathException {
+		for (Map.Entry<String, Class> entry : functionMap.entrySet()) {
+			add(entry.getKey(), entry.getValue());
+		}
+	}
+
+	/**
+	 * Should only your application initialized to
+	 */
+	public static void init() {
+		if (initialized) {
+			return;
+		}
+		functions.putAll(com.jayway.jsonpath.internal.function.PathFunctionFactory.getFunctions());
+		functions = Collections.unmodifiableMap(functions);
+		initialized = true;
+	}
+
+	public static PathFunction newFunction(String name) throws InvalidPathException {
+		// Lazy init
+		init();
+
+		Class functionClazz = functions.get(name);
+		if (functionClazz == null) {
+			throw new InvalidPathException("Function with name: " + name + " does not exist.");
+		} else {
+			try {
+				return (PathFunction) functionClazz.newInstance();
+			} catch (Exception e) {
+				throw new InvalidPathException("Function of name: " + name + " cannot be created", e);
+			}
+		}
+	}
+
+	private static void assertNotInitialized() {
+		if (initialized) {
+			throw new InvalidPathException("Can not change path function factory after it is initialized");
+		}
+	}
+}

json-path/src/main/java/com/jayway/jsonpath/internal/function/PathFunctionFactory.java

@@ -32,6 +32,20 @@ public class PathFunctionFactory {
 
     static {
         // New functions should be added here and ensure the name is not overridden
+        Map<String, Class> map = getFunctions();
+
+        FUNCTIONS = Collections.unmodifiableMap(map);
+    }
+
+    /**
+     * Returns the common/core functions.
+     *
+     * @see #FUNCTIONS
+     * @see PathFunction
+     *
+     * @return Map of path functions keyed by name
+     */
+    public static Map<String, Class> getFunctions() {
         Map<String, Class> map = new HashMap<String, Class>();
 
         // Math Functions
@@ -55,11 +69,11 @@ public class PathFunctionFactory {
         map.put("last", Last.class);
         map.put("index", Index.class);
 
-
-        FUNCTIONS = Collections.unmodifiableMap(map);
+        return map;
     }
 
     /**
+     * @deprecated
      * Returns the function by name or throws InvalidPathException if function not found.
      *
      * @see #FUNCTIONS

json-path/src/main/java/com/jayway/jsonpath/internal/path/FunctionPathToken.java

@@ -4,7 +4,7 @@ import com.jayway.jsonpath.internal.Path;
 import com.jayway.jsonpath.internal.PathRef;
 import com.jayway.jsonpath.internal.function.Parameter;
 import com.jayway.jsonpath.internal.function.PathFunction;
-import com.jayway.jsonpath.internal.function.PathFunctionFactory;
+import com.jayway.jsonpath.PathFunctionFactory;
 import com.jayway.jsonpath.internal.function.latebinding.JsonLateBindingValue;
 import com.jayway.jsonpath.internal.function.latebinding.PathLateBindingValue;